D12
EX-IR
Gas Transmitter with IR Smart Sensor
Dec 2019 ( 85-0004 Rev A)
72
Relay Operation, Menus, and Settings
The following applies to D12 transmitters ordered with 3 SPDT (Form C) relays.
The Alarm Relay option provides three SPDT (Form C) mechanical relays on the Power Supply board.
The relays are rated for 5 amps, non-inductive loads at 250VAC, and are suitable for switching small
loads, such as horns and warning lights, but should not be used to switch motors or other high current,
inductive loads.
Each relay coil may be assigned to one of the four alarms and operate as normally energized (
Norm
=1,
also called “fail-safe”), or normally de-energized (
Norm
=0). Selecting normally energized (1) allows the
relay to indicate an alarm, or a power failure. This selection is made in the Relay Setup Menu on page 74.
The table below details the contact states for the two selections in the no-alarm, alarm, and power fail
conditions.
Table 19. Relay
Coil “Norm”
Setting
No-Alarm
Alarm
Power
Failure
0
(normally de-energized)
Coil
De-energized
Energized
De-energized
Open Contacts
C-NO
C-NC
C-NO
Closed Contacts
C-NC
C-NO
C-NC
1
(normally
energized, “fail
-
safe”)
Coil
Energized
De-energized De-energized
Open Contacts
C-NC
C-NO
C-NO
Closed Contacts
C-NO
C-NC
C-NC